Contents:

Introduction:

Introduction Substation serve as sources of quality energy supply for the local area of distribution in which these are located. Their main functions are to receive energy transmitted at high voltage from the generating station, reduce the voltage to a value appropriate for local distribution and provide facilities for switching.

PowerPoint Presentation:

What is Substation ? The assembly of apparatus used to change some characteristics (e.g. voltage, a.c. to d.c. ,freq, p.f. etc..)of electrical supply is called a substation.

Important Points:

Important Points It should be located at a proper site(i.e. at the center of gravity of load). It should provide safe and reliable arrangement. It should be easily operated and maintained. It should involve minimum capital costs.

Classification of Substation:

Classification of Substation

According to Service requirement:

According to Service requirement Transformer Substation : Transformer are installed to transform power from one level to another as per needs. Switching Substations : This substation meants for switching operation of powerlines with out transforming the voltage. Power factor correction Substation : This substation installed to increase the power factor to minimise losses. Frequency Changer Substation : This substation installed where speed controlled of motor required. Converting Substation : This substation convert a.c to d.c or vice versa. Industrial Substation : This substation installed for supply power only to industry.

According To Constructional Features:

According To Constructional Features Indoor Substation :In this substation the apparatus are installed with in the substation building.This substation employed For voltage upto 11k.v. Outdoor Substation :This subststion are installed in open land.This substation employed For voltage beyond 66k.v. Underground Substation :This substation are installed under the ground in thicky populated city where cost of the land is more. Pole-Mounted Substation :This substation are erect for distribution of power in localities.This is employed for the transformer upto 250 kva.). Foundation Mounted Substation :This substation are installed for transformer which are too heavy.(rating beyond 250Kva).

Substation equipments:

Substation equipments Bus bar :It is the conductor connecting power line to substation equipments. Insulators & fittings :Insulator fix and isolate the bus bar system. Isolating Switch :This is used for disconnecting equipment for maintance and repair. Relays & Circuit Breaker :CB open and close a circuit under normal and fault condition. Power Transformers :These are used in substation to step up or step down the voltage. Instrument Transformer :used for measuring . Metering & Indicating Instrument :used to watch over the circuit quantities. Power line carrier communication systems Coupling capacitors and wave traps

Basic Equipments In A Substation:

Basic Equipments In A Substation

Substation Auxiliary:

Substation Auxiliary AC/DC supply :AC supply is used for substation auxillaries and DC supply for relay operation. Oil handling system : It used for purifying oil from moisture. Illumination : Substation should be properly illuminated for safety. Compressed air system : This system required for functioning of CB. Service bay : These are required to carry the equipments to installation side. Fire extinguishers

Lightning/Surge Arresters:

Lightning/Surge Arresters

Isolating Switch:

Isolating Switch Use three types of crystals Two locking One motive connected to stator Locking mechanism Normally locked: Spindle will not move if no power applied Normally free: Spindle moves under external force